Power distribution systems in an aircraft operate to transfer energy from one part of the aircraft to another. Power may be distributed in various forms, including hydraulically, pneumatically, and electrically. Hydraulic power may be generated by engine driven pumps (EDPs) that are each driven by one of the aircraft main engines. In particular, each main engine of the aircraft may drive either one or two EDPs. The EDPs may be each used to convert mechanical energy generated by the one of the main engines into hydraulic power for consumption by hydraulic loads within the aircraft. Some examples of hydraulic loads within the aircraft include, but are not limited to, hydraulic actuators connected to control surfaces of the aircraft such as ailerons, elevators and rudders, as well as actuators for landing gear and doors. The demand for hydraulic power within the aircraft varies significantly during the different phases of flight. For example, hydraulic flow requirements are typically the lowest during cruise.
Those skilled in the art readily appreciate that fuel costs are a significant factor in operating an aircraft. For most commercial passenger aircraft, the cruise phase of flight usually consumes the majority of fuel. Improving the fuel efficiency of the aircraft to reduce fuel consumption, if done without impairing the operation of the aircraft, is a desirable goal.